Fully Coupled Multiphysics Modeling of Superconductors for Microwave Devices

This article introduces a novel multiphysics modeling framework for the high-fidelity simulation of superconductors in microwave. The proposed approach integrates the time-dependent Ginzburg–Landau (TDGL) equations with full-field radio frequency (RF) finite element method (FEM) simulations to enable seamless coupling between superconducting physics and electromagnetic wave propagation. By relying on standard RF design tools and workflows, this methodology bridges fundamental superconducting phenomena with practical engineering applications, offering designers enhanced simulation accuracy without requiring specialized expertise in superconductor physics. Demonstrative implementations include a microstrip line and a microstrip coupled-line structure, where time-dependent insertion losses, mode impedances, and the dependence of Josephson junctions (JJs) on geometrical dimensions are analyzed. The presented examples relying on the implementation of this novel workflow in the COMSOL Multiphysics platform highlight its potential to predict power-dependent losses and critical thresholds dependence on geometry and temperature, providing crucial insights for the design of high-power RF systems. An extension of the study toward JJs within the same framework is presented, opening the way to fully coupled design methods for quantum sensors relying on both RF fields and Josephson effects. The compatibility of the model with commercial RF tools positions it as a powerful resource for advancing the development of superconducting technologies in microwave engineering.